Means for electroplating



Aug. 9, 1932. PIERSQL I 1,870,743

MEANS FOR ELECTROPLATING' Filed Feb. 15.. 1928 .3 Sheets-Sheet 5 INVENTOR ATTORNEY Patented Aug. 9, 1932 UNITED. STATES PATENT? OFFICE ROBERT J. PIERSOL, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO UNITED STATES CEROMIUH CORPORATION, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF.

- PENNSYLVANIA MEANS FOR ELECTROBLATING Application med February 15, 1923. Serial No. 254,461.

Another object. of my invention is to pro-' vide mechanism for automatically electroplating, particularly chromium plating, a large quantity of articles through the same predetermined schedule.

Another objectof my invention is to provide mechanism for automatically eifecting continuous operations in electroplating processes'in accordance with present day line process commercial production.

Chromium is a desirable plating metal because of its lustrous, nbn tarnishable qualities and general wear resistiveness. It has but slowly come into commercial use, how

ever, because of the general difficulty in obtainmg or maintaining suitableplatin conditions in the solution. Although no considerable diificulty has been involved in individual laboratory platings, the plating. of large quantities of articles has been confronted by many problems of maintaining the plating solution in proper condition to permit continuous operation over anextended period-of time with the'expectationof constant plating As soon as the solution has become uncon conditions and results. To a. greatextent chromium plating of quantities of articles has been done in batches,- rather than continuously,'referring to the use of the solution.

stant, it has been necessary to discard it and use a new solution.

- I have developed a process for treating or conditioning the plating solution to maintain constant plating conditions, which per:

-'mit continuous use of the solution, and in ora 7 der vto fully utilizethe advantages of such a ic apparatus and mechanism,described herein, for continuous plating operations. 7 Present practice in chromium plating involves stop-watch timing by an observer, or individual judgment of the sufficiency of the time of plating. The disadvantages of such operation are reflected in the non-uniformityof the successive plating operations. One of the main objects of my invention is to 'obviate' such methods of human control and the resulting variations in plating results.

The necessity for proper timing is due to the-fact that. chromium plating, as distinguished from plating with other metals, must be done by the still process, in' which the article to be plated must be held' stationary in position relativev to a cooperating electrode, and the time of exposure of the article to the plating solution must not be excessive or a mottled or dull plated surface will result instead of a lustrous surface as desired.

Constant timing with constant bath conditions therefor insures constant conditions and a lustrous surface, where the proper. timing interval has been established fora' particular article. Such timing must be established, if necessary, by experiment.

It should be noted that the timing is primarily to' control-the lustre of'the resulting plated surface. The thickness of the plating determines the current density to be used, and, secondarily, the time of plating or exposure. In general, a thicker plating requires a lower current density and longer time. For the operation discussed herein, a two-minute latlng operation has, been determined to e proper.

Other objects and advantages of themechanism or of the component units will .be pointedout in the specification.

Inasmuch asthe foregoing apparatus was developed for the plating of automobile bumpers in quantity production, the desi and construction to be illustrated will be particularly adapted for such articles. Obviously, the nature or physical contour of the articles to be plated -will go'vern the design or talrrangement of certain parts of the appara s.

The operation may be best described with reference to the accompanying drawings in which Figure 1 is a front view, partially in section, of a plating mechanism embodying my invention, together with a diagrammatic showing of the electric circuits which may be conveniently shown;

Figure 2 is a plan view showing the arrangement of the tanks or vats for the various solutions used in'the plating process.

Figure 3 is a sectional view of the carrier support for the rack, and of the rack for the articles to be plated.

Figure 4 is a plan view of a bracket on the rack for supporting a bumper to be plated and also maintaining electrical engagement therewith. I

Figures 5 and 6 are detail views of latching parts for securing the rack to the carrier support to prevent free oscillation of the rack, and also for mechanically and electrically securing an external current-conduct ing cable to the rack.

Figure 7 is a plan view of a bumper, showing the end eyes or loops whereby the bump er is supported on the rack brackets.

Figure 8 is a plan view of the guides for the racks.

Figure 9 is a side view of a lead electrode for the plating tank.

Figure 10 is a side view ofthe carrier.

mechanism of Figure 1, partially in elevation and partially in section.

Figure 11 is a combined plan and schematic view of the positioning commutator which determines the stopping positions of the carrier above the tanks.

Fi ure 12 .is a'plan sectional'view of the rotating gear and lifting shaft of carrier mechanism.

The apparatus and mechanism comprise, in general, acarrier 20 which carries racks 21 upon which are supported the articles to be plated; tanks or vats 22, containing various solutions to which the articles are to be subjected in the plating process; and sources 23 of electrical energy for the electrolytic cleaning of the articles and for their subsequent plating.

The carrier 20 comprises a vertical cylinder structure 25, a piston shaft 26 movable ve'rtically through the upper end of the cylinder,

and a s 'de 27 ecured tothe shaft and hav- In t s means of the lug and slot construction, relaing apluralityof horizontal arms 28 for supporting the articles to be plated. The cylinder structure embodies a lower portion301of wide bore and an upper portion 31 of narrow bore.

V The lower end of the piston shaft is provided with a piston head 32 which is fitted with piston rings 33to fit the lower bore'of the cylinder.

The 'upper portion 31 of the cylinder rests upon the lower portion 30 and the lower end of the narrow-bore portion 31 serves as an upper stop for the piston. The upper end of the upper, narrow-bore portion 31 is provided with a bearing 34 which serves to guide and support the shaft 26 against lateral movement.

The spider 27 is secured to the upper end of the shaft 26 and israised or lowered with the shaft, to raise or lower its load of material to be acted upon. Movement of the piston, to raise or lower the shaft and its load, is effected by introduction of steam or compressed air into the cylinder head through the port-hole 35 at the base of the cylinder.

v The admission and exhaustion of the lifting medium are controlled through any suitable means, which I have illustrated for this purpose as a two-way valve 36, provided with the extension rod 41 to move'the rod up or down with the shaft 26.

The admission of steam or compressed air into the cylinder raises the shaft and the spider with its load from the several tanks. In order to advance the articles to the next successive positions, the shaft and its load must be turned while in raised position and then lowered.

-a collar 45 and is secured to the upper end of p It is desirable that the articles to be plated occupy a predetermined position in the plating tank, in order that successive plating operations shall be attended by substantially constant conditions. Inasmuch as the operation is automatic, a positioning device is employed to ensure the proper disposition of the articles to be plated.

To efi'ect rotation of the shaft, it is provided with a slot 46 which receives a lug or finger 47 secured to a worm gear 48 surrounding the shaft. The worm gear 48 is driven by a worm 49 secured to the shaft of a motor 50.

The motor and gears are supported in fixed position on the cylinder structure, and, by

tive axial movement is permitted between the shaft and the rotating gear, but not relative circumferential movement. Since the worm gear is practically locked against movement by turning forces on it, the lug serves as a guide for the upward and downward movements of the shaft 26 to confine those movements in definite planes.

In order to define the limits of rotation of the shaft and its load to obtain proper positioning of the articles in the tanks, I provide a positioning device 55 comprising a complete continuous slip ring 56, a segmental ring or commutator 57 and brushes 58 and 59 for respectively engaging the two rings. Both rings are mechanically secured to, but electrically insulated from, the worm gear 48 and rotate therewith. The brushes 58 and 59 are secured in position on the cylinder structure and insulated therefrom.

The segmental ring or commutator 57 is divided into eight segments 60 separated by insulation 61 on theouter periphery of the ring to present separated conducting surfaces to the brush 59. The segments are all electrically connected, however, to the solid stop ring 56.

The commutator may be made-by fitting separate segments to a ring of insulating material, or, preferably by slotting a ring 7 similar to ring 56 to receive small inserts of insulating material in the outer periphery to be engaged by the brush 59.

The circuit of the shaft-rotating motor is controlled by the commutator of the positioning device and also by a switch 63, which is closed when the shaft and its load are in raised position. The switch 63 is mounted on the cylinder structure and is arranged to be operated by a pin 64 on the extension rod 41 when the rod rises to a predetermined position.

The switch comprisestwo circuit closing elements 65 and 66 and a restraining spring 67 which opens both switch elements when the extension rod lowers due to the lowering of the shaft.

In this application, I am concerned only i with the handling and treatment of the bumpers to be plated after the preliminary operations preparatory to the plating sequence. The preliminary operations consist of rolling and shaping the bumper bar; ,picklin to remove scale; grinding and polishing; e ectrolytically cleaning; plating with a thin layer of nickel, a thin layer of copper and .a

thick layer of nickel; polishing to lustre; and

- racking for the chromium plating sequence.

The chromium plating'sequence of operations through which the material to be plated must pass, is then 1st tank, soap wash;

2nd tank, electrolytic cleaning;

3rd'tank, hot wash,

4th tank, plating, 1

5th tank, cold wash,

6th tank, hot wash. Two extra positions are provided; one for racking or placing the racks on the arms at the beginning of the sequence; the other for de-racking or removing the racks from the arms after the completion of the sequence of operations.

v While the time of'operations will vary according to the nature of the articles to be plated, I shall consider the timing as based 7 upon the bumpers for which this equipment was particularly developed.

Since the plating operation is the primary concern, its time interval will determine the operating cycle. A plating period of approximately two minutes is sufiicient to place a lustrous layer of desired thickness upon the bumper surface. The articles must there-- fore remain in the. solutions approximately two minutes. At the end of the two minute interval, the shaft raises the spider support and its load, turns through an angle of 45 degrees and lowers the load into the tanks for the next operations. During the two-minute interval the rack with fully treated articles is removed at the deracking position and a fresh rack with untreated articles placed on the arm then in racking position.

The apparatus thus operates through a time cyclic process plating, and, since each operation depends upon the chromium plating operation, all of the operations must be attended by the best conditions for that time interval. Too long an immersion in some solutions might cause oxidation of. the articles.

'Each operation must therefore be performed underproper conditions for the timing dictated by the chromium operation. 4

The timing cycle is. controlled by a small synchronous motor 70 which drives a drum having three segments 71, 72 and 73 thereon.

The segments 71 and72 are electrically connected, but the segment 73 is insulated from them.

The-motor 70 is connected between contact finger 74 and an emergency stop switch 78 which leads to one conductor of a. control circuit, which may be alternating or direct current, and will be referred to, for convenience, as the negative conductor. The contact fingers 75 and 76-are connected to the positive conductor of the control circuit.

The start contacts of a start-stop switch 79 are connected between the contact fingers 74 and 75 to normally connect those fingers irrespective of the segments 71 and 72 When the stop button is depressed to stop the operation of the mechanism, the start switch,

is opened and the segments 71 and 72 then control the stopping of the motor 70 at a predetermined point in the sequence of operations. In this case the stopping point .has been chosen at the end of the lowering operation, Contact finger 76 is connected to brush 58 of the slip ring 56. Contact finger 7 is connected to brush 59 engaging the segmental ring or commutator 57. Contact finger 77 is also connected through switch .lowering electromagnet 38 which moves valve 36 to fluid-exhausting position. The switch contact of the switch 63 co-operates with the auxiliary switch 80 in controlling the energization of the lowering electromagnet 38.

When the mechanism is to be operated, the arm in racking position is loaded and the start switch 79 depressed. If the switch 78 is closed, the circuit for motor will be completed and the motor energized to rotate the drum and the segments 71, 72 and 73.

At the end of a two-minute interval, segment 73 will bridge contact fingers 76 and 77 thereby completing a circuit from positive control conductor through the coil of auxiliary switch and through raising electromagnet 37 to negative controls conductor. At the same time a circuit is established to switch 66 in the circuit of rotating motor 50. Switch 80 will operate and open the ci-rcuit of electromagnet 38, and electromagnet 37 will operate valve 36 to admit fluid to the cylinder to raise the piston and the shaft 26.

When the shaft 26 reaches its uppermost position, the switch 63 will be closed by the pin 64 on the guide rod 41, thereby completing the circuit of shaft-rotating motor 50, from positive control conductor through segment 73 and contact fingers 76 and 77, switch 66 and motor 50 to negative control conductor.

The motor 50 thereupon turns the worm wheel 48 which turns the shaft 26 and its load toward the vat into which the articles are to 'be immersed.

Until movement of the motor 50, the segmental ring 57 has been in such position that brush 59 engaged an insulating bar between segments. Movement of the segmental ring 57 due to movement of the motor 50 and theworm wheel 48, quickly establishes engagement between the brush 59 and a conducting segment of the ring 57, and thereby establishes a circuit between contact fingers 76 and 7 7 of the timing drum, in parallel with the segment 73. Y

The timing'length of segment 73 is made so as to release control of its circuits to the segmental ring or commutator 57.

The segmental ring 57 maintains the circuits of the motor 50, of the auxiliary switch 80 and of the raising electromagnet 37 until the end of the segment is reached, and the brush then disengages the segment and moves onto the insulating insert.

The motor 50 thereupon stops, its circuit having been opened. The position of the segmental ring has been predetermined so that the arm carrying the loaded rack will be above a definite position in-the tank into which the rack is to be lowered.

The circuits of the auxiliary switch 80 and of the raising electromagnet were also opened by the disengagement of the segment 57 and the brush 59. Both are thereupon de-energized. The auxiliary switch 80 closes the circuit of the lowering electromagnet 38 which had already been established by switch element '65 of switch 63. The valve 36 is thereupon actuated by electromagnet 38 to fluid-exhausting position, and the shaft and its load are gradually lowered. Short downward movement of the shaft 26 and the extension rod 41 permits switch 63 to open and thereby open the circuit of lowering electromagnet 38.

The mechanism remains in lower position for about two minutes, until segment 73 of the timing. drum again engages its contact fingers 76 and 77 to cause the lifting and r0- tation and lowering of the shaft to the next position. Periodically the same operations.

are performed to progressively move the treated articles through the different operations of the plating process.

-When it is desired to stop operation of the mechanism, the stop button of switch 79 is depressed during; the last rinsing operation. 1

The circuit of t e timing motor 70 is opened atswitch 79, but is maintained by segments 71 and 72 until the contact finger 74 disen gages the segment 71. The lower end of segment 71 is slightly lower than the lower end of segment7 3, but not as low as the lower end of segment 72.

The timing motor 7 will stop at the end of the segment 71 but the control of the main mechanism having been assumed by the positioning commutator 57, the shaft and its load willbe controlled until brought to lower deracking position, even though the timing motor has stopped.

Inasmuch as six operations are involved for the entire plating process, the vats or tanks are arranged along the sides of an octagon to allow the space of'two sides to be used for racking and de-racking. A support or spider having eight arms' is therefore employed.

Since the rack on each arm must be supplied with current in both the electrolytic cleaning and the plating tanks, it is desirable to supply current to the racks in a manner that will not interfere with the rotation of the mechanism. With that end in mind, I provide a mercury container 84 of conducting material on the top of the shaft and spider structure but insulated therefrom. An elec- .trode 85 depends into the mercury pool in the container-84 and is supported on a flexibly mounted bracket arm 86 which is-electrically connected to the negative terminal of a generator 87.

'Each arm is provided with a rigid substructure 90 for supporting the racks rigidly to prevent excessive swayin of the racks during turning movement 0 the shaft and spi er. t A plurality of insulators 91 are disposed on each arm and down along the side edges of the sub-structure 90 to support a copper strap 92 or other suitable electrical conduc tor for supplying current to the rack. The conductor 92 on each arm is electrically con 'nected to the mercury'container and is dividedinto two portions 93 supported on both sides of the sub-structure 90. The ends or terminals 94 of the portions 93 are preferably cables, round in shape and relatively free in movement to permit ready attachment to the racks. During non-use the ends 94 are placed in hollow insulated blocks 95 on the substructure.

Each sub-structure 90 is provided with two vertically dependin members 96 to which are secured insulating blocks 97 and a supporting pin 98 electrically insulated from the metal member 96'for supporting the racks 21.

The racks 21 consist of heavy copper straps or bars arranged to constitute two vertical side supports 100 which are held rigidly by suitable copper bracing bars 101 andcross bars 102. The upper ends of'the vertical supports 100 are each provided with a hole 103 for receiving the supporting pins 98 for the racks. A re-inforcing plate-104 serves to strengthen the reduced section of support 100 at the hole 103.

Just below the hole 103 is a clamp 105 for receiving the terminal 94 of the strap conductor 93. The clamp consists of two copper blocks or shoes 106 and 107 provided with semi-circular grooves 108 and 109 which are adapted to receive the cable terminal 94;;

The block 106 is secured to the vertical strap 100 of the rack and the block 107 is support-- ed from a flexibly mounted bracket-111 secured to the vertical strap 100. The blocks are clamped to hold the cable ti ht ly by. means of a pivoted handle 112 an bracket When not in use, the cable is inserted in insulator 110 on the sub-structure. The pivoted handle 112 and the pivoted bracket 13 are supported on the depending members 96 on opposite sides of thesupporting pin 98 and are supported sufiiciently forward on the front surface of the depending member 96 so that the pivoted handle 113 will tightly press the blocks 16 and 17 together when it is forced downward into its co-operating bracket 113.

The clamping handle 112 and the-bracket 113 are secured to thesides of the depending for supporting the bumpers to be plated,

and also to provide a good electrical connection to them. The pins are rovided with vertical, intersecting slots an the resulting resiliency of the parts of the pins ensures good contact with the bumpers.

For thisparticular application the pins 114 are employedto serve both as supports and as current-conducting terminals, because of the bumper design embod g.the end loops or eyes. For plating di erent articles, it will be apparent that modifications may benecessary in the rack structure to support the articles and to conduct current to or from them.

Since it is desired to maintain a definite spacing in the plating tank, between the anodes and the articles to be lated, each rack is provided with two gui e plates 115 secured to the vertical stra s 100 of the rack and extending laterally s ciently to permit the rack to clear co-operating guides 116 disposed vertically along the end surfaces of the plating tank. The guides 116 are of any suitable insulating materiahpreferably slate,

and are provided with guide slots 117 to It is particularly desirable to support the lead electrodes in such manner as to permit them to be easily removed for cleaningdaily, since the lead chromate which forms on the surface interferes with the conductivity of.

the plating solution. Anything which will affect the normal conductivity of the solution should be avoided.

The tanks may be madeiof any suitable material, but the use of steel tanks throughout is preferred. They should be raised and insulated from the floor, particularly those receiving current, such as. the electrolytic cleaning and the plating tanks. In the electrolytic cleaning tank the articles to be plated constitute the anodes, whereas in the plating tank they are the cathodes. The electrode 85 to the mercury pool container 84 is therefore connected tothe negative terminal of the plating generator 87 and to the positive terminal of the cleaning generator 126. I prefer to use separate sources of current for these purposes. They may be 6 driven by individual motors or by the same motor 127, as illustrated.

When operation of the mechanism is to be started, the start switch 79 is depressed to energize the timing motor 70." A rack 10 loaded with bumpers, that have been given the preliminary treatments, is placed upon the arm in racking position. When the segment 7 3 of the timing motor engages its contact fingers 7 6 and 77 the valve 36 is moved to inlet position and the shaft rises with th rack to upper'position.

The rise of the shaft causes the turning motor 50 to be energized through the switch 66 controlled by the pin 64 on the extension rod 41. The motor 50 then turns the shaft and its spider structure until the rack is above the first tank. The circuit of the motor 50 is then opened and the rotation of the shaft is stopped. At the same time, the control circuits of the raising magnet 38 and of the interlock switch 80 are de-energized.

The lowering magnet 37 is thereupon energized to turn the valve 36 to exhaust position to permit the shaft to lower and immerse the rack and its load. in the first tank.

While the apparatus is in lowered position for two minutes, the arm now in rack-- merely unlatching the locking handle 112,

removing the cable 94 and lifting the rack from the pins 98 on the sub-structure.

In order to avoid grounding the cables 94 on the frame of the apparatus, the cables are inserted in the insulators 110 when not in use.

-Whenthe racks are immersed in the electrolytic cleaning tank, the articles to be plated are subjected to a cleaning current from the 6 volt generator 126. When immersed in the plating solution, the articles are traversed bycurrent from the 12 volt generator 87.

The preparation and maintenance ofthe several solutions and particularly of the plat ing solution do not constitute part of my present invention and needs no particular description. The temperature of the solutions may be maintained in any'suitable manner.

' Inasmuch as the current to be conducted to the surface to be plated' will be of the or-- der of 200 amperes per sq. ft. of surface, the

various current-conducting elements should be of suflicient capacity to avoid introducing excessive resistance in the plating current a ing and have the advantages of automatic operation resulting in economic operation and constant plating conditions.

Various modifications may be made in the design or operation of the apparatus without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention 1. Automatic plating apparatus comprising a plurality of spaced tanks arranged in a predetermined sequence and containing solu-. tions to which articles to be plated are to be subjected in definite sequence, a tank containing the plating solution, and electrodes, a carrier embodying means movable in a path related to the location of the tanks, racks for supporting the articles to be plated, locking means on the movable means of the carrier for securing the racks to said movable means.

to prevent oscillation of the racks, a timing device for periodically actuating the carrier to subject the articlesto be plated to the influence of the solutions of the tanks in sequence, means for supplying current to the racks and articles to be plated as they are immersed in the plating solution, and means for positioning the racks with respect to the plating electrodes as the racks are immersed.

t2. Platin apparatus comprising a plurality of tariks arranged in predetermined sequence and containing various solutions for treating an electro-depositing. chromium upon art cles immersed therem, a carrier embodyinga plurality of supporting elements.

movable to co-operative positions relative to the several tanks, racks for the articles to be plated, means for removably securing the racks to the supporting elements of the carrier, means for actuating the carrier to lower the racks into the several tanks, timing means for periodically controlling the actuating means to withdraw the racks from the tanks,

advance the racks to the next tanks in the sequence and lower the racks into those tanks, means for supplying current to the articles when they are lowered into the plating tank, means for fixing the position of the .articles while in the plating tank, and guide members in the plating tank for guiding the racks as they are lowered into position in that tank.

3., Plating apparatus comprising a plurality of tanks arranged in predetermined sequence and containing solutions for treating articles to be plated, a carrier provided with supportin elements movable in a predetermined path relative to the tanks, racks for the articles to be plated, means for remov-' ments, atiming device for periodically efi'ect ing the actuation of the carrier to withdraw the racks and the articles from the several tanks, advance them in position to the next tanks in the sequence and lower them into those tanks, means for supplying current to the articles when they are immersed in the plating solution of the plating tank, electrodes in the plating tank, and means for p0- sitioning the racks with respect to said electrodes when the carrier lowers the various racks into the plating solution.

4.' Plating apparatus comprisin a plu rality of tanks containing solutions or treating articles to be plated according to predetermined steps in a plating process, said tanks including one containing a plating solution and electrodes positioned'to cooperate with the articles to be plated, racks for the elements to be plated, a carrier for the racks for progressively subjecting the articles to the solutions in the tanks inthe predetermined sequence, a timing device for periodically controlling the actuation of the carrier, and means in the plating tank for guiding each rack as it is introduced into the platingtank, to maintain a predetermined spaced relation between the articles to be plated and the electrodes in the plating'solution.

e combination with a conveyor apparatus capable of vertical and horizontal movement and a plurality of tanks containing various solutions to which articles may be progressively subjected by the coveyor apparatus, according to a definite sequence of operations of a process, of means for raising the apparatus vertically to liftthe'articles from'the tanks, means for moving the apparatus horizontally, and means for rendering horizontal movement dependent upon the apparatus being in raised vertical position.

6. In combination, a carrier comprising a vertically disposed cylinder, a shaft disposed therein for verticalireciprocating movement 0 between an upper and a lower position, means for admitting flui'd to and discharging it from the cylinder to raise and lower the shaft, a plurality of tanks disposed around the cylinder and containing solutions in which articles are to be treated, supports on the upper end of the shaft for supporting the articles to be treated, and movable with the shaft to raise and lower the articles from and into the treating solutions, and means for per- 5 mitting rotation of the shaft to move the supports horizontally only when the shaft is in its upper position.

7. The combination with mechanism comthe plunger to rise vertically with the, sup

prising a vertically reciprocable plunger and porting arms and their load and to move the arms and their load horizontally to a 'predetermined position above atank and thenmovement to be dependent upon the horizontal movement.

8. In combination, a carrier capable of vertical and horizontal movement, a plurality of tanks disposed in a predetermined path of movementpf the carrier and containing solutions for treating articles-conveyed by the carrier, of means for automatically controlling the movement of-the carrier in a predetermined path including horizontal and vertical movements and according toa predetermined schedule, and means dependent upon a vertical raising movement for controlling a succeeding horizontal movement and means responsive to the horizontal move ment. for controlling a succeeding lowering vertical movement.

9. In combination, a carrier capable of vertical and horizontal movement, a plurality of tanks disposed in a predetermined path of movement of the carrier and containing solutions for treating articles conveyed by the carrier,'of means for automatically effecting vertical movement of the carrier, means for then efi'ecting horizontal movement thereof, and means for rendering the horizontal move ment dependent upon the vertical movement of the carrier.

10. In combination, a carrier capable of vertical and horizontal movement, a plurality of tanks disposed in a predetermined path of movement of the carrier and containing solutions for treating articles conveyed by the carrier, of means for effecting the raising and lowering of the carrier, means for rotating the carrier comprising a worm and wormwheel drive, means for controlling the extent of rotation of the carrier comprising a commutator switch movable with the carrier and serving toposition the carrier at its lowering position, means responsive tothe rais ng of the carrier for controlling its rotating means, and means responsive to its predetermined rotation for operating the lowering means.

11. Automatic plating mechanism comprising a'plurality of tanks arranged in a definite sequence and containing solutions to'which articles to be plated are to be subjected in the same sequence for operations of the plating process, a carrier capable of horizontal movement between said tanks in sequence and vertical movement above said tanks to lower the articles to be plated into said tanks and to raise them from the tanks, means for raising the carrier, means responsive to predetermined vertical movementof the carrier for effecting horizontal movement of the carrier 8 I emma to advanced position, and means responsive to predetermined horizontal movement for lowering-the carrier at such advanced position.

' 12. In combination, a carrier capable of vertical and horizontal movement, a pluarlity of tanks disposed in a predetermined path of movement of the carrier and containing solutions for treating articles conveyed by the carrier, of means for efi'ecting raising and lowering of the carrier, means for efiecting horizontal movement of the carrier, means responsive to a predetermined raising movement for permitting the horizontal move-' ment, and means responsive to a predetermined horizontal movemeiit for controlling the lowering movement.

13. In combination, a carrier capable of vertical and horizontal movement, a plurality of tanks disposed in a predetermined path of movement of the carrier and containing solutions for treating articles conveyed by the carrier, of means for raising and lowering the carrier, means for horizontally advancing the carrier, means responsive to a predetermlned vertlcal movement for controlling the advancing means, and means controlled by the advancing means for lowering the carrier after a predetermined advance.

In testimony whereof, I have hereunto subscribed my name this 11th day of February,

ROBERT J. PIERSOL. 

